Questions and Answers
What are Wolf-Rayet stars primarily characterized by?
Who discovered Wolf-Rayet stars?
C.J.E. Wolf and G. Rayet
More than 220 Wolf-Rayet stars have been identified.
True
What are the wind speeds of Wolf-Rayet stars?
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What is AB7 also known as?
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Which star is classified as a luminous blue variable?
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AG Pegasi is a binary system composed of a red giant and a white dwarf.
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What is the approximate location of CD Crucis?
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What is the composition of HD 38282?
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R136a1 is known for being one of the most massive stars at what mass?
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What makes hypernovae distinct?
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Study Notes
Wolf-Rayet Stars
- Discovered by C.J.E. Wolf and G. Rayet at Paris Observatory in 1867, with over 220 identified.
- Characterized by extremely high temperatures ranging from 25,000 to 100,000 K.
- Experience mass loss exceeding 10^-5 Solar masses per year.
- Wind speeds can reach between 800 to over 3,000 kilometers per second.
- Typically exhibit rapid rotation and can start from masses under 20 Solar masses; lack dramatic variability.
AB7
- Known as SMC WR7, this binary star is found in the Small Magellanic Cloud.
- Comprises a Wolf-Rayet star and a supergiant companion of spectral type O with a 19.56-day orbital period.
- Surrounded by a bubble nebula.
AB8
- Also referred to as SMC WR8, a binary star in the Small Magellanic Cloud.
- Consists of a Wolf-Rayet star and a main sequence companion of spectral type O, orbiting every 16.638 days.
- Notable for being one of only nine known WO stars and the only one in the SMC not on the nitrogen sequence.
AG Carinae
- A luminous blue variable star in the constellation Carina.
- Recognized as one of the most luminous stars in the Milky Way.
AG Pegasi
- A symbiotic binary star located in the constellation Pegasus, composed of a red giant and a white dwarf.
- The primary has a mass of approximately 2.5 Solar masses, while the secondary is around 0.6 Solar masses.
- Classified as a symbiotic nova with a history of outbursts.
Apep
- A triple star system located in the constellation Norma, including a Wolf-Rayet binary and a hot supergiant.
- Named after the Egyptian serpent deity and surrounded by stellar wind and cosmic dust forming a "pinwheel" shape.
- Identified as a prominent gamma-ray burst progenitor candidate in the Milky Way.
Arches Cluster
- The densest known star cluster in the Milky Way, situated about 100 light-years from its center in Sagittarius.
- Discovered in 1995 and obscured by heavy optical extinction; observed in X-ray, infrared, and radio bands.
- Home to approximately 135 young, massive stars, alongside thousands of less massive stars.
BAT99-98
- A massive star located in the Large Magellanic Cloud, near the R136 cluster in the 30 Doradus nebula.
- Rated at 226 Solar masses and 5,000,000 Solar luminosities, making it one of the most massive and luminous stars.
CD Crucis
- Known as HD 311884, an eclipsing binary star in the constellation Crux, approximately 14,000 light-years away.
- Contains a Wolf-Rayet star, also designated WR 47.
Cygnus X-3
- A high-mass X-ray binary (HMXB) considered a microquasar.
- The only known HMXB with a Wolf-Rayet star, pulling gas from an ordinary star companion.
- Invisible to the naked eye; observable in radio, infrared, X-ray, and gamma-ray spectra.
EZ Canis Majoris
- A binary system in Canis Major, highlighted as one of the ten brightest Wolf-Rayet stars.
- Its primary Wolf-Rayet star shines at an apparent magnitude brighter than 7.
Gamma Velorum
- A quadruple star system in the constellation Vela, one of the brightest stars with a combined magnitude of +1.7.
- Contains the closest and brightest Wolf-Rayet star, known traditionally as Suhail al Muhlif, and modernly as Regor.
GCIRS 13E
- An infrared and radio object near the galactic center, suspected to be a cluster of hot massive stars.
- Potentially harbors an intermediate-mass black hole at its core.
GCIRS 16SW
- A contact binary star in the Galactic Center, with both stars of equal size in orbit every 19.5 days.
- Atmospheres overlap, creating an eclipsing binary with a brightness variation of 0.35 magnitudes in infrared.
HD 5980
- A multiple star system located in NGC 346 within the Small Magellanic Cloud and recognized as one of its brightest stars.
HD 38282
- A massive spectroscopic binary star located within the Tarantula Nebula, made up of two hydrogen-rich Wolf-Rayet stars.
HD 97950
- A multiple star system classified initially as a single star but revealed to be a massive star cluster in the NGC 3603 region.
HD 151932
- A Wolf-Rayet star in the constellation Scorpius, located about 1,300 parsecs from Earth.
- Extremely reddened by interstellar extinction; one of the few visible Wolf-Rayet stars to the naked eye.
Hypernova
- Generated when a very massive star collapses into a black hole.
- Considered a potential source of gamma-ray bursts.
LH41-1042
- A Wolf-Rayet star in the Large Magellanic Cloud and a rare member of the WO oxygen sequence.
LMC195-1
- Another Wolf-Rayet star in the Large Magellanic Cloud, classified as a WO2, likely among the hottest stars known.
Melnick 34
- A binary Wolf-Rayet star located near R136 in the 30 Doradus complex, consisting of highly luminous components.
Romano's Star
- A luminous blue variable star in the Messier 33 galaxy, situated in the constellation Triangulum.
Theta Muscae
- A multiple star system in Musca, recognized as the second-brightest Wolf-Rayet star despite contributions from other massive companions.
VFTS 682
- A Wolf-Rayet star situated in the Large Magellanic Cloud, over 29 parsecs from R136.
- Notable for having 150 Solar masses and 3.2 million Solar luminosities.
Westerlund 2
- An obscured young star cluster about 20,000 light-years away in Carina, estimated to be 1-2 million years old.
- Features some of the hottest and most massive stars known.
NGC 2867
- An elliptical Type II planetary nebula located in the southern constellation Carina.
NGC 3603-A1
- A double-eclipsing binary star at the center of the HD 97950 cluster, notable for being among the most luminous stars.
NGC 3603-B
- A Wolf-Rayet star residing at the center of the HD 97950 cluster, classified as WN6h and highly luminous.
NGC 3603-C
- A single-lined spectroscopic binary system in the HD 97950 cluster, noted for its massive, luminous primary.
R71
- A luminous blue variable star located in the Large Magellanic Cloud with significant luminosity.
R99
- Another highly luminous star in the Large Magellanic Cloud, classified as a possible luminous blue variable.
R136a1
- One of the most massive and luminous stars at 215 Solar masses and 6.2 million Solar luminosities, found at the center of R136 in the Tarantula Nebula.
R136a2
- A prominent Wolf-Rayet star near the center of R136 with a confirmed mass of about 187 Solar masses and luminosity of 5.6 million.
R136a3
- Located near R136a1, this Wolf-Rayet star is one of the most massive and luminous, at 154 Solar masses.
R136b
- A highly luminous Wolf-Rayet star within the R136 cluster in the Large Magellanic Cloud.
R136c
- A massive star in R136, noted for its luminosity and temperature over 40,000 K.
R145
- A spectroscopic binary star in the Tarantula Nebula, both components noted for their exceptional luminosity.
Superluminous Supernovae
- 10 to 100 times brighter than typical supernovae, characterized by long rise times indicating significant mass.
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Description
Explore the fascinating world of Wolf-Rayet stars and their characteristics. This quiz covers key definitions and facts about these massive, rapidly rotating stars, including their identification and mass loss rates.